Halo fans from 16 different countries including the UK were given the chance to take part in a theatrical experience when they travelled to a Halo 'war zone', complete with pyrotechnic explosions and cinematic sound effects and sets.
The experience included 15 actors taking guests on a two-hour adventure that saw them decode a series of clues to fight off the threat of an attack.
Content from the experience will be seeded on social media channels including Facebook and YouTube. PR agency JCPR co-ordinated the journalists invited to the event.
Chris Lewis, vice-president of Microsoft EMEA's interactive entertainment business, said: "From the world's first-ever red-carpet premieres for a video game, to sending a man strapped to a jet-pack 50-foot above London's iconic skyline, 'Halo' launches have continually broken the mould and we are back with a colossal bang for 'Halo 4', transforming a country on the biggest scale imaginable.
Microsoft has already launched a trailer for the game, which was produced by film director David Fincher, the director of 'Fight Club', ahead of its launch on 6 November.
The 'Halo' franchise has sold 46 million copies worldwide since launch in 2001, with Microsoft estimating the franchise is worth $3bn (£1.9bn).Follow @mattchapmanuk